<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        body{
            background-color: aliceblue;
        }

        div{
            width: 300px;
            height: 300px;
            background: linear-gradient(white 50%,black 50%);
            margin: 100px auto;
            display: flex;
            border-radius: 50%;
            align-items: center;


            /* transform-origin: left top;  转的地方*/

            transform: rotate(50deg);

            /* transform: rotateX(50deg);  X轴转*/
        
            transition: all 3s;

        }
        div::before{
            content: "";
            background: radial-gradient(white 25%,black 25%);
            width: 150px;
            height: 150px;
            border-radius: 50%;
        }

        div::after{
            width: 150px;
            height: 150px;
            background: radial-gradient(black 25%,white 25%);
            content: "";
            border-radius: 50%;
        }

        /* rotate 
             正值 正时针
             负值 逆时针
        */

        div:hover{
            transform: rotate(360deg)
        }
        

    </style>
</head>
<body>
    <div>


    </div>
    
</body>
</html>